SignedAlignmentCount on SignedPermutation
The alignments of p: its nesting alignments, those of type EN and those of type NE.
FindStat's St001822 (St001866, St001867, St001868 summed). Not Alignments, which counts the pairs of arcs of an unsigned permutation.
Called as CombinatorialStat(x, "SignedAlignmentCount"). The head's page has its examples.
Live
Distribution
Over SignedPermutations at each size, tallied here in your browser; sizes past 6 are not offered.
FindStat St001822
The number of alignments of a signed permutation.
| Object | Value |
|---|---|
[1] | 0 |
[-1] | 0 |
[1,2] | 0 |
[2,1] | 0 |
[-1,2] | 1 |
[-2,1] | 0 |
[1,-2] | 1 |
[2,-1] | 0 |
Data from FindStat, the combinatorial statistic finder; the page at findstat.org/St001822 has the rest.